In the roads, buildings, storage tanks, automobiles, ships, etc., which are used or located out of doors, an inside temperature thereof is increased when exposed to solar radiation. For this reason, an outside surface of buildings, automobiles, etc., or molded products formed of resin compositions have been painted with a white to light color in order to reflect sunlight thereon, thereby enhancing a heat-shielding effect thereof to some extent.
However, in particular, roofs of buildings exposed to outside are frequently painted with a deep to black color to make stains or contamination thereon unremarkable when viewed from outside. Buildings, automobiles, etc., whose outside surface is painted with a deep to black color, tend to absorb sunlight as compared to those having an outside surface painted with a light to white color, and therefore tend to suffer from considerable increase in inside temperature when exposed to solar radiation. Such a high inside temperature of buildings, automobiles, etc., is undesirable for transportation or storage of products.
From the standpoint of saving energies required for preventing global warming problems, it has been strongly demanded to suppress the increase in inside temperature of buildings, automobiles, etc., whose outside surface exhibits a deep color to a black color.
Hitherto, there are known black pigments comprising Mn and Fe (refer to Patent Documents 1 and 2).
In Patent Document 1, there are described heat-resistant black pigments comprising Mn2O3 and Fe2O3 which have a hematite structure. However, the black pigments described in Patent Document 1 tend to hardly exhibit a sufficient blackness degree.
In addition, in Patent Document 2, there are described black composite oxide particles comprising Mn and Fe which have a non-spinel structure. However, the black composite oxide particles described in Patent Document 2 tend to hardly exhibits a sufficient heat-shielding effect.